Aviation display depiction of weather threats

ABSTRACT

A method for indicating a weather threat to an aircraft is provided. The method includes inferring a weather threat to an aircraft and causing an image to be displayed on an aviation display in response to a determination by aircraft processing electronics that the inferred weather threat to the aircraft is greater than a measured weather threat to the aircraft.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/681,901, entitled “AVIATION DISPLAY DEPICTION OF WEATHERTHREATS,” filed Apr. 8, 2015, which is currently co-pending, which is acontinuation of U.S. patent application Ser. No. 13/246,769, entitled“AVIATION DISPLAY DEPICTION OF WEATHER THREATS,” filed Sep. 27, 2011,each of which are incorporated by reference in their entirety and forall purposes.

BACKGROUND

The present disclosure relates generally to the field of airborne radarsystems. The present disclosure more specifically relates to the fieldof depiction of inferred weather threats on an aviation display.

In general, an airborne weather radar can readily detect precipitation(e.g., rain), which may be used as a surrogate for weather threats to anaircraft. However, some storms (e.g., typhoons) produce significantrainfall but little lightning, hail, turbulence, or other threats to theaircraft; whereas, other weather cells may produce little precipitationbut severe turbulence. Similarly, lightning detectors can readily detectlightning strikes, but do not indicate areas of high electrical energyaround a cell that are not active, but may be induced to strike by thepassage of an aircraft.

Current systems which make inferences regarding weather threats aretypically ground based and make broad predictions about weather. Forexample, National Weather Service severe thunderstorm watches or tornadowatches indicate that conditions are favorable for a thunderstorm ortornado; however, these watches typically cover hundreds of squaremiles, which is generally not helpful in making decisions regardingflying through or around specific weather cells. Thus, there is a needto provide an improved system for indicating an inferred weather threatto an aircraft.

SUMMARY

One embodiment relates to a method for indicating a weather threat to anaircraft, the method including inferring a weather threat to an aircraftand causing an image to be displayed on an aviation display in responseto a determination by aircraft processing electronics that the inferredweather threat to the aircraft is greater than a measured weather threatto the aircraft.

Another embodiment relates to an apparatus for indicating an inferredweather threat to an aircraft, the apparatus including processingelectronics configured to cause an image to be displayed on an aviationdisplay in response to a determination that an inferred weather threatto the aircraft is greater than a measured weather threat to theaircraft.

Another embodiment relates to an aircraft weather radar system, thesystem including a processing circuit configured to determine a firstweather threat using an algorithm using one of 1. a wind speed, a winddirection, and a size of a weather cell, 2. a temperature and areflectivity, 3. a temperature and a reflectivity as a function ofaltitude, and 4. a change in an altitude of an echo top of a weathercell over time. The processing circuit is configured to cause an imageto be displayed on an aviation display in response to the first weatherthreat to the aircraft being greater than a measured weather threat tothe aircraft.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an aircraft control center,according to an exemplary embodiment.

FIG. 2 is a schematic illustration of the nose of an aircraft includinga weather radar system, according to an exemplary embodiment.

FIG. 3 is a block diagram of a weather radar system, according to anexemplary embodiment.

FIG. 4 is a block diagram of the processing electronics of the weatherradar system of FIG. 3, according to an exemplary embodiment.

FIGS. 5A and 5B are schematic illustrations of an aviation displayshowing unmodified and modified radar returns, respectively, in responseto an inferred core threat assessment, according to an exemplaryembodiment.

FIGS. 6A and 6B are schematic illustrations of an aviation displayshowing an inferred overflight threat assessment and a correspondingview from the aircraft control center, respectively, according to anexemplary embodiment.

FIG. 7 is a schematic illustration of an aviation display showing aninferred electrified region around a weather cell, according to anexemplary embodiment.

FIGS. 8A and 8B are schematic illustrations of an aviation displayshowing an inferred high altitude threat and a corresponding view fromthe aircraft control center, respectively, according to an exemplaryembodiment.

FIG. 8C is a schematic illustration of an aviation display showing aninferred high altitude threat, according to another embodiment.

FIG. 9 is a flowchart of a process for indicating a weather threat to anaircraft, according to an exemplary embodiment.

FIG. 10 is a flowchart of a process for indicating a weather threat toan aircraft, according to another embodiment.

DETAILED DESCRIPTION

Referring generally to the FIGURES, systems and methods for indicating aweather threat to an aircraft are described, according to an exemplaryembodiment. An airborne weather radar system is generally configured toproject radar beams and to receive radar returns relating to theprojected radar beams. The projected radar beams generally pass throughair and reflect off of precipitation (e.g., rain, snow, etc.), otheraircraft, and terrain (e.g., a mountain, a building). Using thereflected return data, processing electronics associated with theweather radar system can distinguish between types of precipitation andterrain. Weather radar systems are typically configured to display theprecipitation as measured weather threats in green (light rain), yellow(moderate rain), and red (severe rain). While this “rain gauge” providesvaluable information to the crew, it is not an accurate indicator ofweather threat to the aircraft. For example, tropical cyclones ortyphoons produce tremendous amounts of rain, but they are generally notthreatening to an aircraft because they typically do not produceturbulence, hail, or lightning.

To provide a more accurate weather threat assessment to the crew, otherthreats to the aircraft may be inferred. For example, a core threatassessment (e.g., the probability of hail or lightning within a weathercell) may be inferred based on reflectivity as a function of altitude. Apredictive overflight threat assessment may be inferred based on thegrowth rate and direction of a weather cell below the aircraft.Electrified regions associated with weather cells may not containprecipitation or be actively producing lightning; however, thesethreatening regions may be inferred based on reflectivity and thetemperature at which the reflectivity is occurring. Weather threats(e.g., turbulence, lightning, hail, etc.) associated with the blow off(e.g. anvil) region downwind of a weather cell may be inferred based onwind speed, wind direction, and size of the weather cell. The systemsand methods described below cause an image to be displayed on anaviation display in response to a determination that the inferredweather threat to the aircraft is greater than the measured weatherthreat to the aircraft.

Referring now to FIG. 1, an illustration of an aircraft control centeror cockpit 10 is shown, according to an exemplary embodiment. Aircraftcontrol center 10 includes flight displays 20 which are generally usedto increase visual range and to enhance decision-making abilities. In anexemplary embodiment, flight displays 20 may provide an output from aradar system of the aircraft. For example, flight displays 20 mayprovide a top-down view, a horizontal view, or any other view of weatherand/or terrain detected by a radar system on the aircraft. The views ofweather may include monochrome or color graphical representations of theweather. Graphical representations of weather may include an indicationof altitude of those objects or the altitude relative to the aircraft.Aircraft control center 10 may further include other user interfaceelements such as an audio device 30 (e.g., speaker, electro-acoustictransducer, etc.) and illuminating or flashing lamps 40.

Referring to FIG. 2, the front of an aircraft 101 is shown with aircraftcontrol center 10 and nose 100, according to an exemplary embodiment. Aradar system 300 (e.g., a weather radar system or other radar system) isgenerally located within nose 100 of aircraft 101 or within aircraftcontrol center 10 of aircraft 101. According to various exemplaryembodiments, radar system 300 may be located on the top of aircraft 101or on the tail of aircraft 101 instead. Radar system 300 may include orbe coupled to an antenna system. A variety of different antennas orradar systems may be used with the present invention (e.g., a splitaperture antenna, a monopulse antenna, a sequential lobbing antenna,etc.).

Radar system 300 generally works by sweeping a radar beam horizontallyback and forth across the sky. Some radar systems will conduct a firsthorizontal sweep 104 directly in front of aircraft 101 and a secondhorizontal sweep 106 downward at some tilt angle 108 (e.g., 20 degreesdown). Returns from different tilt angles can be electronically mergedto form a composite image for display on an electronic display shown,for example, in FIG. 1. Returns can also be processed to, for example,distinguish between terrain and weather, to determine the height ofterrain, or to determine the height of weather. Radar system 300 may bea WXR-2100 MultiScan™ radar system or similar system manufactured byRockwell Collins. According to other embodiments, radar system 300 maybe an RDR-4000 system or similar system manufactured by HoneywellInternational, Inc. Radar system 300 may include a terrain awareness andwarning system (TAWS) and coordinate with associated user interfaceelements in aircraft control center 10 (e.g., flashing lights 40,displays 20, display elements on a weather radar display, displayelements on a terrain display, audio alerting devices 30, etc.)configured to warn the pilot of potentially threatening terrainfeatures.

Referring to FIG. 3, a block diagram of a weather radar system 300 isshown, according to an exemplary embodiment. Weather radar system 300 isshown to include a weather radar antenna 310 connected (e.g., directly,indirectly) to an antenna controller and receiver/transmitter circuit302. Antenna controller and receiver/transmitter circuit 302 may includeany number of mechanical or electrical circuitry components or modulesfor steering a radar beam. For example, circuit 302 may be configured tomechanically tilt the antenna in a first direction while mechanicallyrotating the antenna in a second direction. In other embodiments, aradar beam may be electronically swept along a first axis andmechanically swept along a second axis. In yet other embodiments, theradar beam may be entirely electronically steered (e.g., byelectronically adjusting the phase of signals provided from adjacentantenna apertures, etc.). Circuit 302 may be configured to conduct theactual signal generation that results in a radar beam being providedfrom weather radar antenna 310 and to conduct the reception of returnsreceived at radar antenna 310. Radar return data is provided fromcircuit 302 to processing electronics 304 for processing. For example,processing electronics 304 can be configured to interpret the returnsfor display on display 20.

Processing electronics 304 can also be configured to provide controlsignals or control logic to circuit 302. For example, depending on pilotor situational inputs, processing electronics 304 may be configured tocause circuit 302 to change behavior or radar beam patterns. In otherwords, processing electronics 304 may include the processing logic foroperating weather radar system 300. It should be noted that processingelectronics 304 may be integrated into radar system 300 or locatedremotely from radar system 300, for example, in aircraft control center10.

Processing electronics 304 are further shown as connected to aircraftsensors 314 which may generally include any number of sensors configuredto provide data to processing electronics 304. For example, sensors 314could include temperature sensors, humidity sensors, infrared sensors,altitude sensors, a gyroscope, a global positioning system (GPS), or anyother aircraft-mounted sensors that may be used to provide data toprocessing electronics 304. It should be appreciated that sensors 314(or any other component shown connected to processing electronics 304)may be indirectly or directly connected to processing electronics 304.Processing electronics 304 are further shown as connected to avionicsequipment 312. Avionics equipment 312 may be or include a flightmanagement system, a navigation system, a backup navigation system, oranother aircraft system configured to provide inputs to processingelectronics 304.

Referring to FIG. 4, a detailed block diagram of processing electronics304 of FIG. 3 is shown, according to an exemplary embodiment. Processingelectronics 304 includes a memory 320 and processor 322. Processor 322may be or include one or more microprocessors, an application specificintegrated circuit (ASIC), a circuit containing one or more processingcomponents, a group of distributed processing components, circuitry forsupporting a microprocessor, or other hardware configured forprocessing. According to an exemplary embodiment, processor 322 isconfigured to execute computer code stored in memory 320 to complete andfacilitate the activities described herein. Memory 320 can be anyvolatile or non-volatile memory device capable of storing data orcomputer code relating to the activities described herein. For example,memory 320 is shown to include modules 328-338 which are computer codemodules (e.g., executable code, object code, source code, script code,machine code, etc.) configured for execution by processor 322. Whenexecuted by processor 322, processing electronics 304 is configured tocomplete the activities described herein. Processing electronics 304includes hardware circuitry for supporting the execution of the computercode of modules 328-338. For example, processing electronics 304includes hardware interfaces (e.g., output 350) for communicatingcontrol signals (e.g., analog, digital) from processing electronics 304to circuit 302 or to display 20. Processing electronics 304 may alsoinclude an input 355 for receiving, for example, radar return data fromcircuit 302, feedback signals from circuit 302 or for receiving data orsignals from other systems or devices.

Memory 320 includes a memory buffer 324 for receiving radar return data.The radar return data may be stored in memory buffer 324 until buffer324 is accessed for data. For example, a core threat module 328,overflight module 330, electrified region module 332, high altitudethreat module 334, display control module 338, or another process thatutilizes radar return data may access buffer 324. The radar return datastored in memory 320 may be stored according to a variety of schemes orformats. For example, the radar return data may be stored in an x,y orx,y,z format, a heading-up format, a north-up format, alatitude-longitude format, or any other suitable format for storingspatial-relative information.

Memory 320 further includes configuration data 326. Configuration data326 includes data relating to weather radar system 300. For example,configuration data 326 may include beam pattern data which may be datathat a beam control module 336 can interpret to determine how to commandcircuit 302 to sweep a radar beam. For example, configuration data 326may include information regarding maximum and minimum azimuth angles ofhorizontal radar beam sweeps, azimuth angles at which to conductvertical radar beam sweeps, timing information, speed of movementinformation, and the like. Configuration data 326 may also include data,such as threshold values, model information, look up tables, and thelike used by modules 328-338 to identify and assess threats to aircraft101.

Memory 320 is further shown to include a core threat module 328 whichincludes logic for using radar returns in memory buffer 324 to make oneor more determinations or inferences relating to core threats toaircraft 101. For example, core threat module 328 may use temperatureand radar return values at various altitudes to calculate a probabilitythat lightning, hail, and/or strong vertical shearing exists within aweather cell. Core threat module 328 may be configured to compare theprobability and/or severity of the core threat to a threshold valuestored, for example, in core threat module 328 or configuration data326. Core threat module 328 may further be configured to output a signalto display control module 338 indicative of the probability of the corethreat, of the inferred threat level within the weather cell, or of theinferred threat level within the weather cell being greater than themeasured threat due to radar returns from rainfall. The signal mayfurther cause a change in a color on aviation display 20 associated tothe threat level to aircraft 101.

Memory 320 is further shown to include an overflight module 330 whichincludes logic for using radar returns in memory buffer 324 to make oneor more determinations or inferences based on weather below aircraft101. For example, overflight module 330 may be configured to determinethe growth rate of a weather cell and/or the change in altitude of anecho top of a weather cell over time. Overflight module 330 may furtherbe configured to calculate a probability that a weather cell will growinto the flight path of aircraft 101. Overflight module 330 may beconfigured to output a signal to display control module 338 indicatingthe threat of the growing weather cell in relation to the flight path ofaircraft 101. For example, the signal may indicate predictedintersection of the flight path of aircraft 101 and the weather cell,rate of growth of the weather cell, or predicted growth of the weathercell to within a threshold distance of the flightpath of aircraft 101.For example, the signal may cause an icon to be displayed on aviationdisplay 20 in a location corresponding to the growing cell, wherein thesize of the icon may represent the size, amount, or probability ofthreat to the aircraft. Overflight module 330 may be configured toinhibit display of weather far below, and thus not a threat to, aircraft101.

Memory 320 is further shown to include a electrified region module 332which includes logic for using radar returns in memory buffer 324 tomake one or more determinations or inferences regarding potentiallyelectrified regions around the weather cell. For example, electrifiedregion module 332 may be configured to use temperature and reflectivityto determine whether a region around a weather cell is likely to producelightning. Electrified region module 332 may be configured to determinea probability of aircraft 101 producing a lightning strike if theaircraft flies through a particular region based on the reflectivityaround a convective cell near the freezing layer. Electrified regionmodule 332 may further be configured to cause a pattern to be displayedon aviation display 20. For example, electrified region module 332 maybe configured to output a signal to display control module 338indicating the existence, location, and/or severity of risk of theelectrified region.

Memory 320 is further shown to include a high altitude threat module 334which includes logic for using radar returns in memory buffer 324 tomake one or more determinations or inferences regarding threats relatedto a blow off or anvil region of a weather cell. For example, highaltitude threat module 334 may be configured to use wind speed, winddirection, and size of a weather cell to predict the presence of ananvil region downwind of a weather cell that may contain lightning,hail, and/or turbulence. High altitude threat module 334 may beconfigured to cause a pattern to be displayed on an aviation display 20.For example, high altitude threat module 334 may be configured to outputa signal to display control module 338 indicating the existence,location, and severity or risk of the anvil region.

Memory 320 is further shown to include a beam control module 336. Beamcontrol module 336 may be an algorithm for commanding circuit 302 tosweep a radar beam. Beam control module 336 may be used, for example, tosend one or more analog or digital control signals to circuit 302. Thecontrol signals may be, for example, an instruction to move the antennamechanically, an instruction to conduct an electronic beam sweep in acertain way, an instruction to move the radar beam to the left by fivedegrees, etc. Beam control module 336 may be configured to controltiming of the beam sweeps or movements relative to aircraft speed,flight path information, transmission or reception characteristics fromweather radar system 300 or otherwise. Beam control module 336 mayreceive data from configuration data 326 for configuring the movement ofthe radar beam.

Memory 320 is further shown to include a display control module 338which includes logic for displaying weather information on aviationdisplay 20. For example, display control module 338 may be configured todisplay radar return information received from memory buffer 324 and todetermine a gain level or other display setting for display of aninferred threat to aircraft 101 on a weather radar display. Displaycontrol module 338 may be configured to receive signals relating tothreats to aircraft 101 from core threat module 328, overflight module330, electrified region module 332, and high altitude threat module 334.Display control module 338 may further be configured to cause, inresponse to one or more signals received from threat modules 328-334 andthreshold values from configuration data 326, a change in color of aportion of an image on aviation display 20, a pattern to be overlaid onan image on aviation display 20, and an icon to be shown on aviationdisplay 20. Display control module 338 may be configured to cause achange in size, location, shape, or color of the colored regions,patterns, and/or icons in response to updated signals received frommodules 328-336.

Processing electronics 304 may be configured to use none, some, or allof the threat modules 328-334 described above. For example, processingelectronics 304 may have an automatic mode, in which weather radarantenna 310 is automatically controlled (e.g., direction, gain, etc.)and core threat module 328, overflight module 330, electrified regionmodule 332, and high altitude threat module 334 are all processinginformation looking for inferred threats. Processing electronics 304 mayhave a manual mode, in which one or more of core threat module 328,overflight module 330, electrified region module 332, and high altitudethreat module 334 may be disabled, for example, for diagnostic purposes.

Referring now to FIGS. 5A and 5B, schematic illustrations of aviationdisplay 20 showing unmodified and modified radar returns, respectively,in response to an inferred core threat assessment are shown, accordingto an exemplary embodiment. Processing electronics 304 may be configuredto cause aviation display 20 to show measured threats to aircraft 101.For example, in FIG. 5A, light rain is shown as stippled regions 502 a,which is often indicated with a green color. Regions 504 a (shown ascross-hatched) indicate moderate rain, and are usually colored yellow toindicate caution to the crew. Regions 506 a (shown as solid black)indicate heavy rain, and are usually colored red to indicate warning tothe crew. Generally, a crew will always fly through green regions 502,always avoid red regions 506, and use their best judgment on yellowregions 504. In the example shown, a crew heading northeast may decideto bank right and fly through regions 508 a rather than climbing orbanking left to avoid the weather cell directly in front of aircraft101.

As described above, processing electronics 304 uses avionics and radarreturn information to infer a core threat. For example, highreflectivity above the freezing layer indicates a high probability ofstrong vertical shearing in the middle of the weather cell, which inturn indicates a high probability of hail and/or lightning. According toone embodiment, core threat module 328 may provide a core threatprobability to display control module 338, which would be configured tointerpret the probability signal and adjust the color of the imagedisplayed on aviation display 20 accordingly. According to anotherembodiment, core threat module 328 may compare the probability of thecore threat to a threshold value and provide a threat level signal todisplay control module 338. Display control module 338 may then adjustthe color shown on aviation display 20 to represent the threat to theaircraft. For example, referring to FIG. 5B, the core threat levels inregions 502 b do not exceed the moderate or yellow threshold; thusregions 502 b remain colored green. Similarly, the core threat levels inregions 504 b do not exceed the high or red threshold and, therefore,remain colored yellow. Regions 506 b are already at the highest threatlevel, so the regions 506 b remain red. Referring to regions 508 b,processing electronics 304 has inferred a core threat level greater thanthe high or red threshold. Accordingly, processing electronics 304 hascaused the color of regions 508 b to change from yellow to red.Similarly, processing electronics 304 has inferred the core threat inregion 510 b to be a moderate threat and, thus, caused the region 510 bto change from no threat indication to yellow. Armed with this inferredcore threat information, a crew heading northeast will likely not passthrough regions 508 b or 510 b, instead climbing over the cells orbanking left to go around the cells.

In the example above, the image of an increased threat was displayed inresponse to a determination that the inferred weather threat was greaterthan the measured weather threat to the aircraft. It is contemplated,however, that an inference of a lower core threat may cause the colorlevel to be reduced. For example, regions 506 a indicate heavy rainfall,which is in and of itself not a threat to aircraft 101. If the corethreat inference in region 506 a is low, region 506 b may be reduced toa moderate or yellow threat level. It is further contemplated thatregions 508 b of inferred core threat may be displayed as a pattern(e.g., striped pattern, speckled pattern, checkerboard pattern, etc.) ofthe increased threat level color in order to indicate to the crew thatthe increased threat level is an inference.

Referring FIGS. 6A and 6B, schematic illustrations of aviation display20, showing an inferred overflight threat assessment and a correspondingforward view through the windshield of aircraft 101 from aircraftcontrol center 10, respectively, are shown according to an exemplaryembodiment. As shown, processing electronics 304 cause aviation display20 to display radar returns reflecting off the of the moisture withinthe weather cells. For example, region 602 a on display 20 correspondsto a weather cell or cloud 602 b seen to the left of FIG. 6B. Similarly,regions 604 a and 606 a correspond to weather cells or clouds 604 b and606 b, respectively. Cloud 608 b is far below the flight path of theaircraft, and while the current weather within the cells may be severe,it will not effect aircraft 101 (e.g., not be significant to aircraftoperations) as the aircraft overflies weather cell 608 b. Thus,processing electronics 304 inhibits display of the weather cell inregion 608 a of aviation display 20 to prevent the crew fromunnecessarily flying around weather cell 608 b. However, these lowerconvective cells are often below, and thus obscured, by a stratiformcloud layer (e.g., cloud deck), making it difficult, if not impossiblefor the crew to see these developing cells. Accordingly, the currentweather conditions of weather cell 610 b cause processing electronics304 to inhibit the display of weather in region 610 a of display 20, anicon 612 may be displayed in region 610 a to indicate that processingelectronics 304 has inferred that weather cell 610 b poses a potentialhazard to aircraft 101.

Processing electronics 304 may be configured to analyze the growth rate(e.g., the vertical height increase) of a weather cell below aircraft101. The growth rate may be determined from changes in the altitude ofthe echo top of weather cell 610 b over time. A probability that weathercell 610 b will grow into the flight path of the aircraft may becalculated by overflight module 330 and compared to a threshold value.As shown in FIG. 6A, icon 612 is overlaid on the image of measuredweather on aviation display 20, the size of icon 612 being indicative ofthe size of threat to aircraft 101. The size of threat may be a functionof the probability that the weather cell will grow into flight path, howclose the weather cell is predicted to be to the flight path, the growthrate of the cell, and/or the severity of weather within the cell.

According to another embodiment, the growth rate of a weather cell maynot be great enough to grow into the flight path of aircraft 101 whilecruising. However, as aircraft 101 begins to descend or turn, its flightpath may intersect (or nearly intersect) the predicted location of lowerdeveloping activity. Accordingly, processing electronics 304 mayconsider not only the “straight line” flight path of aircraft 101, butthe projected flight path of aircraft 101 according to its flight planor auto-pilot settings. Processing electronics 304 may also cause icon612 to be displayed for quickly developing severe cells outside of theflight path of aircraft 101, thereby alerting the crew to the presenceof these developing cells before they appear as weather on aviationdisplay 20. For example, a series of icons 612 may indicate to the crewthat a larger weather system may be developing.

According to an exemplary embodiment, icon 612 is a yellow cautionaryicon, which is displayed over black (e.g., no measured weather, weatherfar below, etc.) regions of the weather image on aviation display 20.Icon 612 may also be displayed on green (light rain, low threat) regionsto indicate that the weather cell is rapidly growing and may worsen.According to other embodiments, icon 612 may be a pattern (e.g., stripedpattern, speckled pattern, checkerboard pattern, etc.), wherein thepattern may be oriented to indicate a rate or direction of cell growth.

Referring to FIG. 7, a schematic illustration of aviation display 20showing inferred electrified regions 704 (e.g., electrified regions 704a, 704 b, 704 c) around a plurality of weather cells (e.g., weather cell702 a, 702 b, or 702 c) is shown, according to an exemplary embodiment.Processing electronics 304 may be configured to cause imagescorresponding to the measured rainfall in weather cells 702 and imagescorresponding to lightning strikes measured with a lightning detector tobe displayed on aviation display 20. However, convectivity may generateregions 704 of high electrical potential around weather cells 702, whichdo not actively produce lightning and, thus, are not measured ordisplayed as lightning on aviation display 20. As aircraft 101 becomescharged while flying, passage of aircraft 101 through the high voltageregion 704 around weather cell 702 may induce a lightning strike throughaircraft 101.

Processing electronics 304 may be configured to determine or infer theseelectrified regions 704 based on reflectivity and the temperature atwhich the reflectivity is occurring. For example, electrified regionmodule 332 may infer an electrified region based on a reflective regionaround a convective cell near the freezing layer. Further, electrifiedregions 704 typically occur at relatively low altitudes (e.g., 10,000 to25,000 feet), so processing electronics may be configured to furtherinfer electrified regions 704 based on altitude.

In response to an inference of an electrified field, processingelectronics 304 may cause a pattern 706 (e.g., speckled pattern, stripedpattern, checkerboard pattern, etc.), shown as a speckled pattern, to beoverlaid on the image of measured weather on aviation display 20. Thesize and shape of the pattern 706 may change in response to a change ina level of inferred weather threat to aircraft 101. For example, theshape of the speckled pattern 706 may change with updated radarinformation.

According to an exemplary embodiment, pattern 706 is yellow to indicatean elevated cautionary threat level. Since electrified regions 704 aretypically around the weather cell 702, the yellow pattern 706 istypically displayed over a black region (e.g., no measured weather, verylight weather). Yellow pattern 706 may also be displayed over a greenregion (e.g., light rain, low measured threat) to indicated the elevatedinferred threat level. Pattern 706 may be displayed over a yellow region(e.g., moderate rain, medium measured threat level) or a red region(e.g., heavy rain, high measured threat level); however, according to anexemplary embodiment, processing electronics 304 may inhibit pattern 706from being displayed on yellow or red regions because colors alreadyindicate an equal or higher level of threat. It is contemplated that ared pattern may be displayed over a yellow region in order to indicatean a high probability or intensity of an electrified region in a regionof moderate rainfall.

Referring to FIGS. 8A and 8B, schematic illustrations of aviationdisplay 20 showing an inferred high altitude threat and a correspondingforward view through the windshield of aircraft 101 from aircraftcontrol center 10, respectively, are shown according to an exemplaryembodiment. Regions 802 a, 804 a, and 806 a shown on aviation display 20correspond to weather cells or clouds 802 b, 804 b, and 806 b,respectively. Weather cell 806 b is shown to include an anvil 808, whichis formed when a cumulonimbus cell has reached the level ofstratospheric stability. Anvil 808 spreads downwind of the core ofweather cell 806 b and is associated with a variety of threats includingturbulence, lightning, and hail lofted out of the top of the cell. Theseassociated threats, as well as anvil 808 itself, tend to have lowreflectivity and, therefore, are not displayed as measured weather onaviation display 20. Furthermore, anvil 808 may be on the opposite sideof weather cell 806 b from aircraft 101 or may be high above aircraft101 such that the crew can not easily see the size and location of anvil808.

Processing electronics 304 may be configured to determine or inferassociated threat regions 810 a associated with anvil 808 based on windspeed, wind direction, and the size of the cell. For example, highaltitude threat module 330 may infer an associated threat regions 810 aon a downwind side of high altitude, high convectivity cell. In responseto an inference of an associated threat region 810 a, processingelectronics 304 may cause a pattern 812 (e.g., speckled pattern, stripedpattern, checkerboard pattern, etc.), shown as a speckled pattern, to beoverlaid on the image of measured weather on aviation display 20. Thesize and shape of the pattern 812 may change in response to a change ina level of inferred weather threat to aircraft 101. For example, theshape of the speckled pattern 706 may change with updated radarinformation. According to one embodiment, the stripes of pattern 812 areoriented in the direction of the wind. According to another embodiment,shown in FIG. 8C, processing electronics 304 may cause boxes 814 to bedisplayed around associated threat regions 810.

As described above with respect to pattern 706, pattern 812 may beyellow to indicate an elevated cautionary threat level. According to anexemplary embodiment, pattern 812 may be displayed or black (e.g., nomeasured weather, very light weather) or green (e.g., light rain, lowmeasured threat) regions to indicate the elevated inferred threat level;however, pattern 812 may not be displayed over a yellow (e.g., moderaterain, medium measured threat level) or a red (e.g., heavy rain, highmeasured threat level) region as these regions already indicate an equalor higher level of threat.

Referring to FIG. 9, a flowchart of a process 900 for indicating aweather threat to an aircraft 101 is shown, according to an exemplaryembodiment. Process 900 is shown to include the steps of inferring aweather threat to an aircraft 101 (step 902) and causing an image to bedisplayed on an aviation display in response to a determination byaircraft processing electronics that the inferred weather threat to theaircraft is greater than a measured weather threat to the aircraft (step904).

Referring to FIG. 10, a flowchart of a process 950 for indicating aweather threat to an aircraft is shown, according to another embodiment.Process 950 is shown to include the steps of determining a measuredweather threat to an aircraft based on a rainfall rate (step 952),inferring a weather threat to aircraft 101 based on a wind speed, a winddirection, and a size of a weather cell (step 954), and inferring aweather threat to aircraft 101 based on a temperature and reflectivity(step 955). Process 950 is further shown to include the step of causing,in response to a determination that the inferred weather threat toaircraft 101 is greater than the measured weather threat to aircraft101, a pattern overlaid on an image indicating the measured weatherthreat to the aircraft to be displayed on aviation display 20 (step956). The size and/or the shape of the pattern may be changed inresponse to a change in a level of inferred threat to aircraft 101 (step958).

Various alternate embodiments of process 950 are contemplated. Process950 may not include all of the steps shown. For example, process 950 maynot include only one of the steps of inferring a weather threat toaircraft 101 based on a wind speed, a wind direction, and a size of aweather cell (step 954) or inferring a weather threat to aircraft 101based on a temperature and reflectivity (step 955). According to anotherembodiment, process 950 may not include the step of changing the size orshape of the pattern in response to a change in a level of inferredweather threat to aircraft 101 (step 958). The steps of process 950 maybe performed in various orders. For example, determining measuredweather threats (step 952) and inferring weather threats (steps 954,955) may be performed in any order or simultaneously.

The construction and arrangement of the systems and methods as shown inthe various exemplary embodiments are illustrative only. Although only afew embodiments have been described in detail in this disclosure, manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, etc.). For example, the position of elements may bereversed or otherwise varied and the nature or number of discreteelements or positions may be altered or varied. Accordingly, all suchmodifications are intended to be included within the scope of thepresent disclosure. The order or sequence of any process or method stepsmay be varied or re-sequenced according to alternative embodiments.Other substitutions, modifications, changes, and omissions may be madein the design, operating conditions and arrangement of the exemplaryembodiments without departing from the scope of the present disclosure.

The present disclosure contemplates methods, systems and programproducts on any machine-readable media for accomplishing variousoperations. The embodiments of the present disclosure may be implementedusing existing computer processors, or by a special purpose computerprocessor for an appropriate system, incorporated for this or anotherpurpose, or by a hardwired system. Embodiments within the scope of thepresent disclosure include program products comprising machine-readablemedia for carrying or having machine-executable instructions or datastructures stored thereon. Such machine-readable media can be anyavailable media that can be accessed by a general purpose or specialpurpose computer or other machine with a processor. By way of example,such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, CD-ROMor other optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to carry or storedesired program code in the form of machine-executable instructions ordata structures and which can be accessed by a general purpose orspecial purpose computer or other machine with a processor. Wheninformation is transferred or provided over a network or anothercommunications connection (either hardwired, wireless, or a combinationof hardwired or wireless) to a machine, the machine properly views theconnection as a machine-readable medium. Thus, any such connection isproperly termed a machine-readable medium. Combinations of the above arealso included within the scope of machine-readable media.Machine-executable instructions include, for example, instructions anddata which cause a general purpose computer, special purpose computer,or special purpose processing machines to perform a certain function orgroup of functions.

Although the figures may show a specific order of method steps, theorder of the steps may differ from what is depicted. Also two or moresteps may be performed concurrently or with partial concurrence. Suchvariation will depend on the software and hardware systems chosen and ondesigner choice. All such variations are within the scope of thedisclosure. Likewise, software implementations could be accomplishedwith standard programming techniques with rule based logic and otherlogic to accomplish the various connection steps, processing steps,comparison steps, and decision steps.

What is claimed is:
 1. A method, comprising: determining a first threatlevel associated with a threat posed to an aircraft by a weathercharacteristic based on radar return data; detecting a weather threat tothe aircraft; determining a second threat level posed to the aircraft bythe weather threat; and causing a pattern to be overlaid on an image ofthe weather characteristic displayed on an aviation display, wherein thepattern is overlaid on a location of the aviation display correspondingto the location of the weather characteristic in response to determiningthat the second threat level is greater than the first threat level. 2.The method of claim 1, wherein the pattern comprises a speckled patternallowing an underlying color of the weather characteristic to showthrough between the speckles.
 3. The method of claim 1, furthercomprising detecting the weather threat to the aircraft based on atleast one of a wind speed, a wind direction, and a size of a weathercell, and wherein the weather threat comprises a blow off region.
 4. Themethod of claim 3, wherein the weather threat to the aircraft is locatedin a region downwind of the weather cell, and wherein the weather cellis capable of producing at least one of hail, lightning, and turbulence.5. The method of claim 1, further comprising detecting the weatherthreat to the aircraft based on a temperature and reflectivity, whereinthe weather threat comprises an electrified region capable of producinga lightning strike.
 6. The method of claim 5, wherein the electrifiedregion is a non-active high voltage region, and wherein the aircraftincreases a likelihood of the non-active high voltage region striking.7. The method of claim 1, further comprising changing at least one ofthe size and shape of the pattern in response to a change in a level ofthe detected turbulence threat to the aircraft.
 8. The method of claim1, wherein the weather characteristic is a precipitation rate.
 9. Anapparatus, comprising: processing electronics configured to: determine afirst threat level associated with a threat posed to an aircraft by aweather characteristic based on radar return data; determine a weatherthreat to the aircraft; determine a second threat level posed to theaircraft by the weather threat; cause a portion of an image of theweather characteristic displayed on a display to be adjusted based onthe second threat level exceeding the first threat level.
 10. Theapparatus of claim 9, wherein the processing electronics are configuredto cause a color of a portion of the image to be adjusted in response tothe probability of at least one of hail, lightning, and turbulencewithin a weather cell exceeding a threshold.
 11. The apparatus of claim10, wherein adjusting the color of a portion of the image compriseschanging the color to a color indicating an increased severity.
 12. Theapparatus of claim 9, wherein the processing electronics are configuredto cause a portion of the image to change color based on temperature andreflectivity as a function of altitude.
 13. The apparatus of claim 9,wherein the processing electronics are configured to adjust a color of aportion of the image in response to at least one of an inference oflightning and hail within a weather cell.
 14. The apparatus of claim 10,wherein the weather characteristic is a precipitation rate and theweather threat is turbulence.
 15. A system, comprising: a processingcircuit configured to: determine a first threat level associated with athreat posed to an aircraft by a weather characteristic based on radarreturn data; determine a weather threat to the aircraft using analgorithm to infer one of a blow off region from an anvil, anelectrified region of airspace, an updraft, and whether a weather cellwill grow into a path of the aircraft; determine a second threat levelposed to the aircraft by the weather threat; and cause an icon to beoverlaid on an image of the weather characteristic displayed on anaviation display in response to the second threat level exceeding thefirst threat level.
 16. The system of claim 15, wherein the weather cellis at an altitude below the aircraft, and wherein the processing circuitis further configured to determine a growth rate of a weather cell. 17.The system of claim 15, wherein the weather threat to the aircraft isdetermined based on a probability that a weather cell will grow into theflight path of the aircraft.
 18. The system of claim 17, wherein thesize of the icon is representative of a size of the weather threat. 19.The system of claim 18, wherein the processing circuit is furtherconfigured to adjust the size of the icon based on how close a weathercell is predicted to be to a current or predicted flight path of theaircraft.
 20. The system of claim 15, wherein the blow off region froman anvil is inferred from a wind speed, a wind direction, and a size ofa weather cell, wherein the electrified region of airspace is inferredfrom a temperature and a reflectivity, wherein the updraft is inferredfrom a temperature and a reflectivity as a function of altitude, andwherein whether a weather cell will grow into a path of the aircraft isinferred from a change in an altitude of an echo top of a weather cellover time.